Narrative:

En route from ZZZ - ZZZ1; the captain's oxygen mask was removed from storage box to be used. As it was removed; the hose to the oxygen mask split and oxygen was leaking at a fast rate. The mask was removed at the quick disconnect; but the split in the hose was located on the aircraft side. Tape from the medical kit was used to wrap the oxygen hose. This slowed the leak but it continued. The hose was then kinked and taped again. Company was contacted and dispatch ran the numbers. We declared an emergency and descended to FL250 direct to ZZZ1. Once at FL250 the leak stopped at 650 psi. Continued on to ZZZ1. After landing all appropriate logbook entries were completed. No further action was required.

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Original NASA ASRS Text

Title: A B737 NG EXPERIENCED AN CREW O2 SYSTEM LEAK BECAUSE OF A SPLIT HOSE IN THE CAPTAIN'S MASK. THE FLT CREW DECLARED AN EMERGENCY AND DESCENDED TO A LOWER ALT.

Narrative: ENRTE FROM ZZZ - ZZZ1; THE CAPT'S OXYGEN MASK WAS REMOVED FROM STORAGE BOX TO BE USED. AS IT WAS REMOVED; THE HOSE TO THE OXYGEN MASK SPLIT AND OXYGEN WAS LEAKING AT A FAST RATE. THE MASK WAS REMOVED AT THE QUICK DISCONNECT; BUT THE SPLIT IN THE HOSE WAS LOCATED ON THE ACFT SIDE. TAPE FROM THE MEDICAL KIT WAS USED TO WRAP THE OXYGEN HOSE. THIS SLOWED THE LEAK BUT IT CONTINUED. THE HOSE WAS THEN KINKED AND TAPED AGAIN. COMPANY WAS CONTACTED AND DISPATCH RAN THE NUMBERS. WE DECLARED AN EMER AND DSNDED TO FL250 DIRECT TO ZZZ1. ONCE AT FL250 THE LEAK STOPPED AT 650 PSI. CONTINUED ON TO ZZZ1. AFTER LNDG ALL APPROPRIATE LOGBOOK ENTRIES WERE COMPLETED. NO FURTHER ACTION WAS REQUIRED.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.